(c) The open loop transfer function of a unity feedback system is given by 350 (-0.2) G(s) (s - 4)(s+d)(52 - 4s +5)(s2 +
Posted: Sun May 15, 2022 2:43 pm
(c) The open loop transfer function of a unity feedback system is given by 350 (-0.2) G(s) (s - 4)(s+d)(52 - 4s +5)(s2 + 25 - 3) where the constant d is a real number. Find all the poles of the open loop transfer function G(s). () The Nyquist diagrams of G(s) for d = 0.75 and d = 2 are given in Figures 3.2 and 3.3, respectively. For each case, using the Nyquist stability criterion, determine the number of poles of the closed-loop system in the right-half plane. Hence, determine the stability of the closed-loop system when d = 0.75 and d = 2, respectively. [8 marks] Nyquist diagram for d-0.75 Imaginary Axis 2 0 -1.5 -1 -0.5 Real Axis Figure 3.2 Nyquist diagram for 2 0.5 Imaginary Axis -0.5 -1.6 -14 -12 -1 -0.8 -06 Real Axis -0.4 -02 0 Figure 3.3